I use Thunderbird since 2003. So you expect me, someone who never has used another program, to know I have to start Mail in order to change the default to Thunderbird.
That doesn't make any sense. If it is a setting that influences the system it should be a system setting not in some different program I might or might not use.
That doesn't make any sense. If it is a setting that influences the system it should be a system setting not in some different program I might or might not use.